The present invention relates to a vacuum processing apparatus for subjecting an object, such as an LCD (liquid crystal display) substrate and semi-conductor wafer, to a predetermined process.
In general, a vacuum processing apparatus for subjecting an object, such as an LCD substrate and semiconductor wafer, to a predetermined process has a load-lock chamber equipped with a transfer arm means and a process chamber arranged adjacent to the load-lock chamber. These chambers are set in the predetermined vacuum state. Those objects set in the load-lock chamber are transferred, one by one, out of the load-lock chamber into the process chamber with the use of the transfer arm means. In the process chamber, the object is subjected to a predetermined process and, after being processed in the process chamber, is returned again back to the load-lock chamber.
A stage (susceptor) is provided in the process chamber to place a to-be-processed object thereon.
FIGS. 4 and 5 show one conventional form of a vacuum processing apparatus. As shown in FIG. 4, the vacuum chamber apparatus has a process chamber 1 for subjecting a semiconductor wafer W, as an object to be processed, to a predetermined process. A stage (susceptor) 2 is located at a bottom side of the process chamber 1 to place the wafer W thereon. At the lower side of the process chamber, a lamp unit 4 is provided to heat the wafer W through the stage 2.
The lamp unit 4 includes a plurality of halogen lamps 3 and is mounted at a lamp housing 8. The lamp housing 8 is mounted on the upper end of a shaft 5 vertically extending on the lower side of the process chamber 1. The shaft 5 is rotatably journaled by a bearing 7 on a support body 6. A rotation drive mechanism (not shown) is connected to the lower end side of the shaft 5. When the shaft 5 is rotated at a rate of, for example, 10-odd revolutions per minute through the rotation drive mechanism, then, in accordance therewith, the lamp unit 4 mounted on the lamp unit 4 is rotated. As shown in FIG. 5, the lamp unit 4 has reflectors 3a each plated with gold.
In the case where the wafer W is heated by the lamp unit 4 equipped with the halogen lamps 3, the lamp housing 8 and its surrounding areas become high in temperature. This produces the problem of the halogen lamp 3 being shorter in service lift due to the overheating of the halogen lamp and the gold-plated portions of the reflector 3a being deteriorated. In order to prevent such a problem, a passage 9 leading to the peripheral area of the halogen lamp 3 is provided in the shaft 5 as shown in FIG. 5. The shaft 5 and lamp housing 8 are cooled by supplying cooling air through the passage 9. Even if the lamp housing 8 is cooled only by air supplied through the passage 9, it is not possible to lower the temperature of the lamp unit 4 which reaches a temperature of nearly 400.degree. C. down to nearly 350.degree. C. Therefore, the apparatus cannot continuously operate for a longer period of time. Further, the service life of the lamps 3 is also shorter and it is necessary to frequently changes lamps.